Wednesday, March 14, 2012

Another Sun Panorama

Just another picture of the Sun, this one taken last Saturday when I was finally able to get it between the clouds after three days of shut-out. Or rather, when I was finally able to get the six different pictures that I stitched together to make it. This version is only 1200 by 1200 pixels, but the full picture is 4500 by 4500!


Just like my picture from last year with the planets, this picture was made using the 11-inch solar telescope we have at the Vis – though unlike last year's, this picture was made by directly connecting my camera to the telescope, rather than shooting through an eyepiece. This caused the Sun to overflow the field of view of my camera, which allowed me to take multiple photos and combine them into this panorama.

It's a bit disappointing in this picture, but that sunspot group near the bottom was one of the largest I've ever seen when I first set eyes on it on Wednesday. By Saturday as you can see it had diminished somewhat – although it's still larger than all the inner planets, and probably larger than the ice giants Uranus and Neptune too.

As a side note, while combining the pictures that make up the final image, I discovered an incredibly useful and easy way to do so. Simply setting the mode of a picture on top to "difference" allowed me to easily see how much, well, difference there was between two photos. The difference mode subtracts one photo from the other pixel by pixel. If the pixels are identical in color to each other, you'll get black. If not, you'll get something that depends on how different they are.

For something fairly featureless like the Sun in white light, it's then a simple matter of moving the upper photo around to minimize the difference as much as possible (which in practical terms, means maximizing the blackness, since the closer the two photos are to each other, the more they cancel each other out and make black). Once you have the maximum amount of black you can set the mode back to normal, and marvel at how closely the photos merge together (although I still spent the better part of an hour manually smoothing and blending the edges). I'm sure this is probably standard panorama-making procedure that people learn about in Photography 101, but I'm really happy to have stumbled upon it. Can't wait to try it on my next set of Moon panorama photos!

3 comments:

  1. Looks great! You should do a sunspot time-lapse!

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  2. Beautiful. Can't wait for the Moon picture.

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  3. A sunspot time lapse would be interesting. Hard, but interesting... I'll have to think about that.

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